1. Field of the Invention
This invention relates to windshield encapsulation and, more particularly, to apparatus and methods for curing an adhesive promoter on a windshield in preparation for encapsulation.
2. The Background Art
Traditionally, the methods used to encapsulate a windshield for introduction into an automobile involve adding an adhesive sealant and a trim to the outside edges of a windshield, while the windshield is still on the assembly line. More particularly, the prior art offered methods consisting of the addition of an adhesive sealant to the windshield, an application of a decorative trim to the peripheral edges of the glass, and a plurality of mechanical fasteners or metal clips connecting the windshield to the vehicle frame to maintain the windshield within the channel-groove of the automobile. However, these traditional methods are characterized as being time consuming and labor intensive.
To improve the existing practices within the industry, a process of employing conventional gasket compression and injection molding techniques was introduced. However, because of the types of materials used in molding the gaskets, the conventional compression and injection molding techniques were later found to lack the proper adhesion qualities between the gasket and the metal body parts, as well as the gasket adhering to the peripheral edges of the windshield. The deficiency in proper adhesion between the windshield and the channel-groove of the automobile frame resulted in water leaks, wind noise, and other related problems. Thus, to accommodate the compression and injection molding techniques and the problems of insufficient adhesion, additional mechanical fasteners were needed to secure the windshield to the body panels.
Because of the disadvantages of improper adhesion, an improvement in prior art methods followed. A unitary windshield assembly consisting of a sheet of glass, an adjoining frame, and a casing or gasket of molded material, such as polyvinylchloride or urethane, was introduced to the industry. The unitary windshield became recognized as a significant improvement over the existing prior art methods because the windshield assemblies arrive at the point of installation, and are ready to be incorporated into the automobile.
These unitary window assemblies are typically made by encapsulating the edge of the windshield with a urethane gasket to which a frame may be attached. Whereby, the sheet of glass and the frame are retained collectively together. A number of fasteners may then be provided at spaced locations along the frame, such that the entire assembly may be guided into precise alignment over the channel-groove of the vehicle frame.
Several steps, however, are dictated before the urethane or polyvinylchloride gasket can be secured to the windshield. First, an adhesive promoter substance should be administered to the glass surface and then permitted to cure before the gasket is applied. Currently, the industry typically applies an adhesive promoter to the windshield, and stores the windshield in a high humidity setting for a period up to 24 hours to allow the windshield to cure before the gasket molding can be applied thereto.
Because the adhesive promoter must be allowed to completely cure before applying the urethane gasket, there are significant disadvantages in the existing curing practices. First and foremost, the present curing practices prove to be severely time consuming. Whereby, a windshield is customarily cured for a period of 24 hours after applying an adhesive promoter delineating a substantial period of time invested before the windshield is ready for encapsulation and introduction into the automobile.
An additional disadvantage involves the costs incurred for having to store the windshields in relatively large, high humidity rooms to cure the adhesion promoter properly. The size of the high humidity storage rooms become necessary to achieve any substantial output of cured windshields ready for encapsulation within a timely fashion.
Consequently, the current practices in the industry to cure the windshield assemblies for encapsulation are considerably labor intensive, requiring more than one employee to maneuver around the large racks of windshields undergoing the curing process. Unfortunately, the methods of curing large quantities of windshields at each setting, tend to produce a substantial number of defective products.
Considering all these factors, the known prior art methods involved in curing an adhesive promoter onto a windshield for encapsulation by a molded gasket before introduction into the automobile involve large investments of time, resources and manpower to produce quality products.